Glow discharge display device

ABSTRACT

Electrical glow discharge display device comprising first and second sets of spaced elongate conductors. The conductors of the first set cross those of the second set to form a cross-bar addressing system for the resulting electrode pairs at the cross points of the conductors of the first set with those of the second. Said electrode pairs define an array of individually addressable glow-discharge paths through a gas atmosphere contained in the device. The conductors are supported in the desired configuration by means of fibres of electrically insulating material such as fibre glass with which they are interwoven. The fibres substantially completely surround each individual discharge path to separate it from the adjacent paths. The weave may be supported between a pair of plates, one of which is transparent, and which are sealed together around their edges to contain the discharge gas.

United States Patent 1191 Schofield Aug. 13, 1974 GLOW DISCHARGE DISPLAY DEVICE Primary ExaminerRonald L. Wibert [75] Inventor' 3:223:32: 32 3:5 3? 32: 5 Assistant Examiner-Richard A. Rosenberger Attorney, Agent, or FirmrFrank R. Trifari; Carl P. [73] Assignee: U.S. Philips Corporation, New Steinhauser York, N.Y. [22] Filed: Apr. 19, 1973 1 l l d SBSTIZACI'I d I p ectnca g ow 1sc arge 1sp ay ev1ce compnsmg [21] Appl' 352582 first and second sets of spaced elongateconductors.

The conductors of the first set cross those of the sec- [30] F i A li ti P i it D t ondls et tolform 51 cross-bartaddressingsystegt lfor the 19 B u 2 9 7 resu tlng e ectro e pairs at t e cross points 0 t e con- May 72 Grat mam 135 2 ductors of the first set with those of the second. Said [52] Us Cl 313/217, 313/210, 313/220, electrode pairs define an array of individually address- 313/268 able glow-d1scharge paths through a gas atmosphere [51] Int CL D I H01 j U02 contained in the device. The conductors are supported [58] Fieid of 1 3/1 217 220 in the desired configuration by means of fibres of electrically insulating material such as fibre glass with which they are interwoven. The fibres substantially [56] References Cited completely surround each individual discharge path to separate it from'the adjacent paths. The weave may be UNITED STATES PATENTS supported between a pair of plates, one of which is 2,925,525 2/1960 Dav1s 313/108 B transparent, and which a Sealed together around their edges to contain the discharge gas. 3,681,655 8/1972 Toombs .1: 313/217 x 5 Claims, 6 Drawing Figures PAIENTEDMJB I 31914 3.829.734

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' Slit! zor 2 1 GLOW DISCHARGE DISPLAY DEVICE The invention relates to an electrical glow-discharge display device comprising first and second sets of spaced elongate conductors, with the conductors of each set extending substantially parallel to each other and crossing those of the other set to form a cross-bar addressing system for the resulting electrode pairs at the cross-points of the conductors of the first set with the conductors of the second set, said electrode pairs defining an array of individually addressable glowdischarge paths through a gas atmosphere contained in said device. Such a device may be used for displaying patterns such as diagrams, numerals, words or the like.

One device of this kind is that of Lears-Siegler reported in Electronics News of July 26,-1965. This device comprises an array of gas-discharge cells formed by a two-dimensional matrix of small apertures in a sheet of insulating material placed between a pair of plates each carrying an electrode system of parallel semi-transparent conductive strips, the two sets being orthogonal to form a cross-bar arrangement. Each aperture lies at the cross-point of a strip of one system with a strip of the other. It is an object of the invention to provide an alternative construction for such an array of gas-discharge cells.

British Patent Specification 1,252,838 discloses a glow-discharge display device of the A.C. type ile. one in which the electrodes are electrically insulated from the discharge gas atmosphere. In this device the electrodes and a cross-bar addressing system therefor are formed by interwoven electrically insulated wires.

The present invention provides an electrically glowdischarge display device of the kind mentioned in the preamble, characterized in that said conductors are supported in said configuration by means of fibres of electrically insulating material with which there are interwoven, said fibres substantially completely surrounding each individual said path.

The conductors can be bare but are preferably coated with an electrically resistive layer to make the individual glow-discharges along a conductor independent of each other. The fibres are preferably made of glass.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawing in which:

FIG. 1 is a perspective view of a gas discharge display device according to the invention,

FIG. 2 is a plan view of one conductor-insulating fibre weave which may be used in the device of FIG. 1,

2 are spaced apart by means of a spacer frame 3 of the same material, the frame 3 extending completely around the edges of the plates 1 and 2 to enclose a space between the plates. Row and column conductors 4 and 5 respectively of a cross-bar addressing system emerge from between the spacer 3 and the plate 1 and the spacer 3 and the plate 2 respectively. The plates 1 and 2 are sealed all round to the spacer 3 in a vacuumtight manner by means of a suitable solder-glass enamel e.g. pyroceram (not shown) a frit of which may alternatively replace the spacer 3, and the space between the plates 1 and 2 contains a suitable glass-discharge atmosphere such as a Penning gas mixture or pure neon at a pressure of a few hundred Torr, and an array of individually addressable electrode pairs defining an array of glow-discharge paths through the gas atmosphere. Two possible constructions for this array will be described with reference to FIGS. 2 and 3 respectively.

FIGS. 2 and 3 show part of one possible construction in which the row and column conductors 4 and 5 extend alternately over and under one another and are interwoven in the manner shown with multi-stranded soft glass fibre cord 6 which is sealed between the plates 1 and 2 and the spacer 3 in such manner that it is taut. Because the cord 6 is taut it holds the row and column conductors 4 and 5 apart at their cross-points by an amount approximately equal to the cord thickness. Similarly each row or column conductor is spaced from the next by approximately twice the cord thickness. It will be seen that the cords 6 substantially completely surround each individual gas-discharge path between a conductor 4 and a conductor 5 at their crosspoints thereby tending to isolate each discharge path from the adjacent paths.

The construction shown in FIGS. 2 and 3 suffers from the disadvantage that, if the conductors and 5 are used as anodes and cathodes respectively, oi vice versa, anode and cathode conductors alternate at each face of the array. The light output from such gas discharges is not in general symmetrical with respect to the anode and cathode and thus the discharges are likely to appear differently depending on whether the anode or cathode is facing the observer. An alternative construction which eliminates this disadvantage is shown in FIGS. 4, 5 and 6.

In FIG. 4 the conductors 4 and 5 are substantially straight and are held in two separate but interlocking weaves of fibre-glass cords 6 and 7 respectively. The conductors 4 alternate with thicker fibre-glass cords 8 and the conductors 5 alternate with thicker fibre-glass cords 9. The weave of components 4, 6 and 8 is the same as that of components 5, 7 and 9 the former being reversed and rotated through relative to the latter, the latter being laid over the former to provide a selflocating and interlocking system. The method of location can be seen more clearly from the cross-sections shown in FIGS. 5 and 6, FIG. 5 being taken in the plane of the cross-points of conductors 4 and 5 and FIG. 6 being taken through the points of contact of the two weaves. The spacing of the plane of the conductors 4 from the plane of the conductors 5 (13 in FIG. 5) is now about the thickness of a thicker cord 8 or 9, and the cords 6, 7, 8 and 9 now isolate each cross-point from the neighbouring cross-points substantially completely. Again the conductors 4 and 5 and the cords 6, 7, 8 and 9 are sealed between the plates 1 and 2 and the spacer 3 so that they are taut.

The conductors 4 and 5 may be made of the material available under the trade name Telcosil 6" which has an expansion coefficient matched to that of the soft glass parts of the device.

The size and pitch of the array may be chosen at will. The discharge paths may be e.g. 1.5 millimetres between centres and the separation of the conductors defining each discharge path may be 0.75 millimetres thereat. In the embodiment of FIG. 4 conductors 4 and 5 may be 0.2 mm in diameter, glass fibres 8 and 9 may be 0.4 mm in diameter, glass fibres 6 and 7 may be 0.1 mm in diameter, and the distances 10, l1 and 12 may be 2.0 mm, 2.0 mm and 0.8 mm respectively.

What is claimed is:

1. Electrical glow-discharge display device comprising first and second sets of spaced elongate conductors with the conductors of each set extending substantially parallel to each other and crossing those of the other set to form a cross-bar addressing system for the resulting electrode pairs at the cross-points of the conductors of the first set with the conductors of the second set, said electrode pairs defining an array of individually addressable glow-discharge paths through a gas atmosphere contained in said device, said conductors being supported in said configuration by means of fibres of electrically insulating material with which they are interwoven, said fibres substantially completely surrounding each individual said path.

2. A device as claimed in claim 1, wherein the conductors are coated with an electrically resistive layer.

held by the seal so that they are taut. 

1. Electrical glow-discharge display device comprising first and second sets of spaced elongate conductors with the conductors of each set extending substantially parallel to each other and crossing those of the other set to form a cross-bar addressing system for the resulting electrode pairs at the cross-points of the conductors of the first set with the conductors of the second set, said electrode pairs defining an array of individually addressable glow-discharge paths through a gas atmosphere contained in said device, said conductors being supported in said configuration by means of fibres of electrically insulating material with which they are interwoven, said fibres substantially completely surrounding each individual said path.
 2. A device as claimed in claim 1, wherein the conductors are coated with an electrically resistive layer.
 3. A device as claimed in claim 1 wherein the conductors are bare.
 4. A device as claimed in claim 1 wherein the fibres are made of glass.
 5. A device as claimed in claim 1 wherein the conductors and fibres are supported between a first transparent plate and a second plate which are substantially parallel and which are sealed together around their edges to form an envelope containing said gas atmosphere, said conductors being led out through the seal between the plates and the conductors and fibres are held by the seal so that they are taut. 